Light-emitting structure

ABSTRACT

A light-emitting structure, comprising: a first light-emitting structure unit and a second light-emitting structure unit, adjacent to and spaced apart from each other; and an electrical connection arranged on the first light-emitting structure unit and the second light-emitting structure unit, and electrically connecting the first light-emitting structure unit and the second light emitting structure unit; wherein the first light-emitting structure unit comprises a first side surface and a second side surface; wherein the first side surface is between the first and the second light-emitting structure units, and the second side surface is not between the first light-emitting structure unit and the second light-emitting structure unit; and wherein the first side surface is inclined and a slope of the first side surface is gentler than a slope of the second side surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application a continuation-in-part application of U.S. patentapplication Ser. No. 15/196,717, entitled “LIGHT EMITTING STRUCTURE”,filed on Jun. 29, 2016, which claims the right of priority based on U.S.patent application Ser. No. 14/924,264, entitled “LIGHT EMITTINGSTRUCTURE”, filed on Oct. 27, 2015, now U.S. Pat. No. 9,406,719, whichclaims the right of priority based on U.S. patent application, Ser. No.13/230,988, entitled “LIGHT EMITTING STRUCTURE”, filed on Sep. 13, 2011,now U.S. Pat. No. 9,196,605, which claims the right of priority based onU.S. provisional application Ser. No. 61/382,451, filed on Sep. 13,2010, and the content of which is hereby incorporated by reference inits entirety.

TECHNICAL FIELD

The present application relates to a light-emitting structure, and moreparticularly to a light-emitting structure having at least twolight-emitting structure units and an electrical connection forconnecting the light-emitting structure units.

DESCRIPTION OF BACKGROUND ART

A light-emitting diode array is constructed by electrically connectingseveral light-emitting diodes in series or parallel. One diode iselectrically separated from another by a trench or groove. To connectthe separated diodes, metal line(s) or film(s) can be used to span thetrench between the diodes. However, the metal line(s) or film(s) can beeasily damaged during the manufacturing process due to a high aspectratio of the trench.

SUMMARY OF THE DISCLOSURE

An embodiment of the present application discloses a light-emittingstructure, comprising: a first light-emitting structure unit and asecond light-emitting structure unit, adjacent to and spaced apart fromeach other; and an electrical connection arranged on the firstlight-emitting structure unit and the second light-emitting structureunit, and electrically connecting the first light-emitting structureunit and the second light emitting structure unit; wherein the firstlight-emitting structure unit comprises a first side surface and asecond side surface; wherein the first side surface is between the firstand the second light-emitting structure units, and the second sidesurface is not between the first light-emitting structure unit and thesecond light-emitting structure unit; and wherein the first side surfaceis inclined and a slope of the first side surface is gentler than aslope of the second side surface.

Another embodiment of the present application discloses a light-emittingstructure, comprising: a first light-emitting structure unit and asecond light-emitting structure unit, adjacent to and spaced apart fromeach other, wherein the first light-emitting structure unit comprises astep-like side surface facing the second light-emitting structure unit;an insulating layer, formed on the step-like side surface; and anelectrical connection, formed on the insulating layer and electricallyconnecting the first light-emitting structure unit and the secondlight-emitting structure unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional view disclosing a connectionbetween two light-emitting structure units in accordance with anembodiment of the present invention;

FIG. 2 illustrates a top view of light-emitting structure units inaccordance with an embodiment of the present invention;

FIG. 3 illustrates a filling of the trench in accordance with anembodiment of the present invention;

FIG. 4 illustrates a top view of an electrical connection over a trenchin accordance with an embodiment of the present invention;

FIG. 5 illustrates a top view of an electrical connection over a trenchbetween two light-emitting structure units in accordance with anotherembodiment of the present invention;

FIG. 6 illustrates a cross-sectional view of interconnections betweenlight-emitting structure units in accordance with one embodiment of thepresent invention;

FIG. 7 illustrates a cross sectional view of several light-emittingstructure units in accordance with an embodiment of the presentinvention;

FIGS. 8A-8F illustrate steps of forming light-emitting structure unit inaccordance with an embodiment of the present invention; and

FIG. 9 illustrates a cross sectional view of a light-emitting structureunit in accordance with an embodiment of the present invention;

FIG. 10 illustrates a top view of light-emitting structure units inaccordance with an embodiment of the present invention;

FIG. 11 illustrates a cross sectional view of the light-emittingstructure unit along the line C-C′ of FIG. 10.

DESCRIPTIONS OF EMBODIMENTS

FIG. 1 illustrates a cross-sectional view disclosing a connectionbetween two light-emitting structure units in accordance with anembodiment of the present invention. Each of the left light-emittingstructure unit 10A and the right light-emitting structure unit 10Bincludes a lower layer (11A, 11B), an upper layer (12A, 12B), alight-emitting junction (13A, 13B) between the lower layer (11A, 11B)and the upper layer (12A, 12B), and a current spreading layer (14A,14B), which are sequentially formed on a substrate (not shown) byepitaxial growth or bonding method such as metal boding, fusion bonding,and glue bonding.

The left light-emitting structure unit 10A and the right light-emittingstructure unit 10B can be supported by a common substrate or discretesubstrates, and electrically separated by a trench 15. For example, thelight-emitting structure units 10A and 10B can be commonly formed on asingle bulk substrate, such as sapphire, GaAs, Si, metal, glass, or PCB;or each light-emitting structure unit is formed on its independent bulksubstrate as described aforementioned, while each independent bulksubstrate can be further integrated together by mechanical gadgets,organic material, metallic material, or any combination thereof Thetrench 15 is formed to reach to, enter in, or penetrate the substrate orany layer between the units. The trench 15 has a cross-sectional profileof at least one rounded edge and/or at least one chamfered edge. Therounded edge and/or the chamfered edge can be formed on a single layeror several layers. For example, as shown in the drawing, the roundededge and/or the chamfered edge can be formed on the lower layer 11Aand/or the lower layer 11B. However, the rounded edge and/or thechamfered edge can be also formed on both of the upper layer and thelower layer. The rounded edge preferably has a radius R not less than 1μm. The chamfered edge can have two equal or different bevel lengths(L_(bevel)).

Moreover, a sidewall of the trench is inclined by more than 80 degreeagainst the bottom surface of the lower layer. For example, the angle θbetween the sidewall and the bottom surface of the lower layer, asillustrated in the drawing, is smaller than 80 degree, 70 degree, 60degree, 50 degree, or 40 degree. The angle θ can also fall within aspecific range, such as 80 degree˜70 degree, 70 degree˜60 degree, and 60degree˜40 degree. Besides, the trench may have sidewalls inclined atsimilar or different angles. For example, one sidewall is inclined at anangle of 50 degree˜40 degrees; the other sidewall is inclined at anangle of 60 degree˜50 degree. Provided one or more sidewalls areinclined, the trench can have a trapezoid cross section having a height,a longer side, and a shorter side parallel to the longer side. Theheight is close to the thickness of the lower layer or the totalthickness of the upper layer and the lower layer. For example, theheight is between 1 μm˜10 μm; the longer side has a length of 3 μm˜100μm; the shorter side has a length of 1 μm˜40 μm; the ratio of the longerside to the short side is between 3:1 and 1.5:1. Specifically, theheight is between 4 μm˜9 μm; the length of the longer side is between 5μm˜40 μm; the length of the shorter side is between 2.5 μm˜20 μm.

To build an electrical passage between the units, an electricalconnection 18 bridges the trench 15 and electrically connects any twolayers, which do not belong to the same unit, of the lower layer 11A,lower layer 11B, upper layer 12A, and upper layer 12B. For example, theunits can be coupled together in series connection by bridging the lowerlayer 11A and the upper layer 12B, or the upper layer 12A and the lowerlayer 11B; the units can be coupled in parallel connection by bridgingthe upper layer 12A and upper layer 12B.

To prevent the electrical connection 18 from unintentionally contactingwith other layer, an isolation layer 16 can be also provided on thetrench 15 and some areas near the trench opening, such as thesidewall(s) of the lower layer 11A and/or the lower layer 11B, theedge(s) of the trench 15, the sidewall(s) of the upper layer 12A and/orthe upper layer 12B, the top surface(s) of the upper layer 12A and/orthe upper layer 12B, and/or the bottom surface(s) of the currentspreading layer 14A and/or the current spreading layer 14B. Optionally,an isolation layer 17 can be further provided between the isolationlayer 16 and the electrical connection 18. The isolation layer 17 can beused to fill the empty space between the isolation layer 16 and theelectrical connection 18, to fill voids on the isolation layer 16, tosmooth the outer surface of the isolation layer 16, to fill the trench15, to form a flat plane for laying the electrical connection 18, tocover area(s) not under the shade of the isolation layer 16, to improveESD protection, and/or to support the electrical connection 18.

The isolation layer 16 can have an edge with an acute angle; the layerlaid on the isolation layer 16 therefore can smoothly cover the drop onthe edge of the isolation layer 16. The slope of the edge can releasethe stress concentrated on the layer over the drop. The acute angle canbe less than 90, 80, 70, 60, or 50 degree. Besides the isolation layer16, the isolation layer 17 can also have an edge with an acute angle.

In addition, to protect the electrical connection 18 from oxidation,erosion, and/or damage, a passivation 19 can be formed on the electricalconnection 18. The passivation 19 can cover not only outer surface(s) ofthe electrical connection 18 but also the area beyond the outersurface(s). Specifically, the passivation 19 can be further formed onany surfaces of the isolation layer 17, the current spreading layer 14A,the current spreading layer 14B, the upper layer 12A, the upper layer12B, the lower layer 11A, and/or the lower layer 11B.

FIG. 2 illustrates a top view of light-emitting structure units inaccordance with an embodiment of the present invention. In the drawing,four rectangular light-emitting structure units 1, 2, 3, 4 are deployedin a 2×2 array; however, the shape, the number, and the deployment ofthe light-emitting structure units are only illustrative but not tolimit applications and variations of the present invention.

The light-emitting structure units 1, 2, 3, 4 are laterally separated bytrenches 15. An electrical connection 18 can bridge the trench 15 fromone light-emitting structure unit (for example, unit 3) to anotherlight-emitting structure unit (for example, unit 4) and couple the twounits in series or parallel connection. As shown in cross section AA′,the trench 15 (for example, between units 1 and 4) on which noelectrical connection 18 is formed has steeper sidewalls, therefore,more volume of the light-emitting structure unit resides nearby thetrench 15. In contrast, as shown in cross section BB′, the trench 15(for example, between units 3 and 4) on which the electrical connection18 is formed has less steep sidewalls in comparison with the sidewallsin the cross section AA′. In one embodiment, some of the light-emittingstructure units are removed to form a trench having a ladder-shaped,and/or inclined sidewall. In other words, the trench has areversed-trapezoid or quasi-reversed-trapezoid cross-sectional profile.For example, the method for forming the trench can be selected from wetetching, dry etching, laser machining, diamond scribing, and anycombination thereof. In general, the steeper the sidewall is, theshorter the processing time is taken.

In addition, the less steep sidewall can be formed on either a fulllength trench L_(full) or a partial length trench L_(partial) (asillustrated in FIG. 2). The full length trench L_(full) herein isdefined as a trench having a length similar to the width of thelight-emitting structure unit; the partial length trench L_(partial) isdefined as a trench has a length smaller than the width of thelight-emitting structure unit. For example, L_(partial) is between 10μm˜100 μm; the width of the light-emitting structure unit is between 100μm˜1000 μm; the ratio of L_(partial) to width of the light-emittingstructure unit is between 1:2˜1:10. Moreover, the electrical connection18 can be further connected with a current network 20 through whichcurrent can come from or flow to a position far away from the electricalconnection 18, as shown in FIG. 5.

FIG. 3 illustrates a filling of the trench. In step (1), an isolationlayer 21 and a lower electrical connection 22 a are sequentiallyprovided on a trench 23 which is formed between two light-emittingstructure units 24, 25. The isolation layer 21 can separate the lowerelectrical connection 22 a from contacting with the light-emittingstructure units 24, 25. The lower electrical connection 22 a canelectrically link two light-emitting structure units 24, 25. The lowerelectrical connection 22 a can be formed by deposition and etchingprocesses. Because the trench 23 has a tapered cross section, theinclined portion of the lower electrical connection 22 a thereforeusually is thinner than the flat portions thereof, and can be easilydamaged during following processes. To reinforce the inclined portion ofthe lower electrical connection 22 a, an upper electrical connection 22b is further provided on the lower electrical connection 22 a. The upperelectrical connection 22 b is preferably provided on the top of theinclined portion or within the trench 23, as shown in step (2).

FIG. 4 illustrates a top view of an electrical connection over a trenchbetween two light-emitting structure units in accordance with oneembodiment of the present invention. The electrical connection 250 has abridging portion 250 a over the trench 23 and two joining portions 250b. Each of the two joining portions 250 b is electrically connected toan anode or a cathode on each of the two light-emitting structure units26. The bridging portion 250 a has a BB cross section; the joiningportion 250 b has an AA cross section. The BB cross section has a widthgreater than that of the AA cross section, while the two cross sectionscan have equal or close area for achieving a constant or even electricalcurrent per cross sectional area. For example, the bridging portion 250a has a width of 5 μm˜50 μm; the joining portion 250 b has a width of 3μm˜15 μm while both of them has a thickness close to 8 μm. However, thetwo cross sections can also have different area according to user'srequirements or practical manufacturing processes. The bridging portion250 a can be constructed after the basic electrical connectionmanufacturing process is completed. For example, the electricalconnection 250 over the trench 23 which has inclined sidewalls isfirstly formed by depositing metal on specific areas of the trench 23and the light-emitting structure units 26. But the deposited metal onthe inclined sidewalls of the trench 23 is usually thinner than thedeposited metal on the light-emitting structure unit 26, and thedeposited metal bridging the two light-emitting structure unitstherefore has various cross sectional area. To increase the volume orthe cross sectional area of the metal over the trench 23, anextra-deposition process is further applied on the thinner depositedmetal area to form the bridging portion 250 a as described above.Furthermore, the volume or the cross sectional area of the electricalconnection 250 over the trench 23 can be increased by other methods,such as bonding one or more supplement articles on the thinnerelectrical connection portions, and depositing other material(s). Thesupplement article is such as metal and ceramic. Moreover, the thickerelectrical connection portions can be even thinned down to the levelsimilar to the portions over the trench 23.

FIG. 5 illustrates a top view of an electrical connection 250 over atrench 23 between two light-emitting structure units in accordance withanother embodiment of the present invention. Each of the light-emittingstructure unit 26 includes a lower layer 27 and an upper layer 28 havinga smaller area than that of the lower layer 27. The lower layer 27 has amesa area 29 surrounding the upper layer 28. The light-emittingstructure unit 26 can emit light from a light-emitting layer which ispositioned within the upper layer 28 or between the upper layer 28 andthe lower layer 27. Provided the light-emitting layer is positionedwithin the upper layer 28, the upper layer 28 can include a p-typesemiconductor layer and an n-type semiconductor layer, between which thelight-emitting layer is sandwiched; and the lower layer 27 can include acarrier for supporting the upper layer 28. The upper layer 28 can beepitaxially grown on the lower layer 27, or be integrated with the lowerlayer 27 by glue bonding, metal bonding, fusion bonding, or eutecticbonding. Provided the light-emitting layer is positioned between theupper layer 28 and the lower layer 27, either the upper layer 28 or thelower layer 27 can include a p-type semiconductor layer, and the othercan include an n-type semiconductor layer.

To build a current passage from one light-emitting structure unit toanother, an electrical connection 250 is provided on the twolight-emitting structure units 26. As shown in the drawing, one end ofthe electrical connection 250 is installed on the upper layer 28, andthe other end is installed on the lower layer 27. However, the two endsof the electrical connection 250 can be also installed on two upperlayers 28 or two lower layers 27. The electrical connection 250 can beconstructed by metal, semiconductor, metal oxide, or any combinationthereof. Provided a metal oxide, which has higher transparency than thatof metal, is used to form the electrical connection 250, fewer lightescaping areas are therefore shaded by the electrical connection 250.The metal oxide is such as ITO, IZO, and CTO.

FIG. 6 illustrates a cross-sectional view of interconnections betweenlight-emitting structure units in accordance with one embodiment of thepresent invention. Each light-emitting structure unit 26 includes anupper layer 28 and a lower layer 27 formed on a common substrate 30 byepitaxial growth and/or bonding method. The bonding method includes butnot limited to metal bonding, eutectic bonding, glue bonding, and fusionbonding. A light-emitting zone 31 is sandwiched by the upper layer 28and the lower layer 27. The light-emitting zone 31 can generate lightwhen a bias voltage is imposed on the upper layer 28 and the lower layer27. The light from the light-emitting zone 31 radiates isotropically.

Two light-emitting structure units 26 are separated by a trench 23.Provided the two light-emitting structure units 26 are coupled in seriesconnection, an isolation layer 21 is formed on the trench 23 to leavethe electrical connection 250 touching the upper layer 28 of onelight-emitting structure unit 26 and the lower layer 27 of anotherlight-emitting structure unit 26. In this embodiment, the isolationlayer 21 is formed to expose not only the top surface but a portion ofthe sidewall of the lower layer 27. The exposure of the sidewall of thelower layer 27 can increase the contact area between the electricalconnection 250 and the lower layer 27, and accordingly the currentdensity can decrease.

FIG. 7 illustrates a cross sectional view of several light-emittingstructure units in accordance with an embodiment of the presentinvention. The several light-emitting structure units 26 are supportedby a substrate 30. Two neighboring light-emitting structure units 26 areseparated by a trench 23. In the present embodiment, the trench 23 istrapezoid-shaped and has a narrower top opening and a wider bottom. Thelight-emitting structure unit 26 nearby the trench 23 therefore has anundercut sidewall with a degree greater than 90 degree, as shown in thedrawing. In other words, the light-emitting structure unit 26 has areversed trapezoid shape. Provided the light-emitting structure unit 26can emit light from the middle part, the central part, or the upper partof the reversed trapezoid, the light moving backwards can leave the unit26 on the benefit of the undercut sidewalls. The trapezoid-shaped trenchcan be formed by using over etching process.

In accordance with one embodiment of the present invention, thelight-emitting structure unit can include at least a first conductivitylayer (for example, the upper layer), a conversion unit (for example,the light-emitting zone), and a second conductivity layer (for example,the lower layer). Each of the first conductivity layer and the secondconductivity layer has a single layer or a group of multiple layers(“multiple layers” means two or more layers), and the two single layersor the two groups of the multiple layers, which are respectively locatedon the first and the second conductivity layers, have distinctpolarities or distinct dopants. For example, the first conductivitylayer is a p-type semiconductor layer; the second conductivity layer isan n-type semiconductor layer. The conversion unit disposed between thefirst conductivity layer and the second conductivity layer is a regionwhere the light energy and the electrical energy could be transferred orinduced to transfer. The one that the electrical energy can betransferred to the light energy is such as a light-emitting diode, aliquid crystal display, and an organic light-emitting diode. The onethat the light energy can be transferred to the electrical energy issuch as a solar cell, and an optoelectronic diode.

The transferred light emission spectrum of the light-emitting diode canbe controlled by changing the physical or chemical arrangement of onelayer or more layers in the light-emitting diode. The light-emittingdiode can be composed of several materials, such as the series ofaluminum gallium indium phosphide (AlGaInP), the series of aluminumgallium indium nitride (AlGaInN), and/or the series of zinc oxide (ZnO).The conversion unit can be configured to be a single heterostructure(SH), a double heterostructure (DH), a double-side doubleheterostructure (DDH), or a multi-quantum well (MWQ). Besides, thewavelength of the emitting light could be controlled by changing thenumber of the pairs of the quantum well.

The material of the substrate(s) used for growing or supporting thelight-emitting structure unit(s) can include but not limits to germanium(Ge), gallium arsenide (GaAs), indium phosphide (InP), sapphire, siliconcarbide (SiC), silicon (Si), lithium aluminium oxide (LiAlO2), zincoxide (ZnO), gallium nitride (GaN), aluminum nitride (AlN), glass,composite, diamond, CVD diamond, diamond-like carbon (DLC) and anycombination thereof.

FIGS. 8A through 8F illustrate a method of forming light-emittingstructure unit(s), or more specific to light emitting diode structures,in accordance with another embodiment of the present invention. Firstly,referring to FIG. 8A, a substrate 41 is provided. The material of thesubstrate 41 can be silicon, silicon carbide, sapphire, arsenide,phosphide, zinc oxide, and magnesium oxide. Then, a 1st semiconductorlayer 42 which is an epitaxy layer of first conductivity, an activelayer 43, and a 2nd semiconductor layer 44 which is an epitaxy layer ofsecond conductivity are formed on the substrate 41. The material of the1st semiconductor layer 42 and the 2nd semiconductor layer 44 includebut not limited to an indium-containing nitride semiconductor, analuminum-containing nitride semiconductor, and a gallium-containingnitride semiconductor. The material of the active layer 43 include butnot limited to indium gallium nitride, indium gallium aluminumphosphide, aluminum gallium nitride, aluminum gallium arsenide, andindium gallium arsenide.

Referring to FIGS. 8B-8D, a multi-step patterning process is performed.Firstly, a first region of the 2nd semiconductor layer 44 is defined sothat the 2nd semiconductor layer 44 has a concave portion 45 therein byphotolithography and etching technology. Then, as shown in FIG. 8C, asecond etching process is performed to etch away partial of the 2ndsemiconductor layer 44 and partial of the active layer 43 until asurface of the 1st semiconductor layer 42 is exposed. Finally, as shownin FIG. 8D, a third pattern process is performed to divide the 1stsemiconductor layer 42 by forming a trench 46 therebetween through thephotolithography and etching technology. After the multi-step patterningprocess, light emitting diode structure are divided with the step-likesidewall profiles as shown in FIG. 8D.

Referring to FIG. 8E, an insulating layer 47 is further formed betweentwo divided light emitting diode structures 40 to cover the step-likesidewalls of the adjacent light emitting diode structures. Wherein, theinsulating layer 47 is made of dielectric material such as siliconnitride, silicon oxide, aluminum oxide, and the combination thereof.Then, as shown in FIG. 8F, a conductive structure 48 is formed on theinsulating layer 47 to electrically connect the 1st semiconductor layer42 of the left light emitting diode structure and the 2nd semiconductorlayer 43 of the right light emitting diode structure in series. Inaddition, a 1st electrode 49 a and a 2nd electrode 49 b can also beformed at the same step or in the different steps while the conductivestructure 48 is formed.

In addition to the patterning process mentioned above, the step-likesidewalls could also be formed by using a gray-tone mask or by ahalf-tone mask. Taking advantage of different opening ratio existing ona single mask, the step-like sidewall profile can be formed through aone-step exposure.

Referring to FIG. 9, through the step-like sidewall structure, light (asindicated by arrows) comes from different angles can be extracted moreeasily because the light can go out to the sidewall of the lightemitting diodes from different angles, and therefore a better lightextraction ability of the light emitting diode structure could beachieved. Besides, because the slope of the step-like sidewalls isgentle, the coverage profile of the insulating layer and the conductivestructure on the light emitting diode can be more uniform.

FIG. 10 shows a top view of light-emitting structure in accordance withanother embodiment of the present invention. FIG. 11 shows a crosssection of the light-emitting structure along line C-C′ shown in FIG.10. The light-emitting structure in the present embodiment comprises afirst light emitting structure unit 6 and a second light-emittingstructure unit 7 adjacent to the first light emitting structure unit 6,and they are separated by a first trench 65. The first light-emittingstructure unit 6 and a second light-emitting structure unit 7 arecommonly formed on a substrate 5. An electrical connection E is arrangedon the first light-emitting structure unit 6 and the secondlight-emitting structure unit 7 and electrically connects the firstlight-emitting structure unit 6 and the second light-emitting structureunit 7. The first light-emitting structure unit 6 includes a lower layer61, an upper layer 62, and an active layer 63 between the lower layer 61and the upper layer 62, which are sequentially formed on a substrate 5by epitaxial growth or bonding method such as metal boding, fusionbonding, and glue bonding. The upper layer 62 locates on of the lowerlayer 61, and the lower layer 61 comprises a mesa area M surrounding theupper layer 62 from the top view of the light-emitting structure. In theembodiment, the first light-emitting structure unit 6 further comprisesa first current spreading layer 64 formed on the upper layer 62 forfacilitating the current spreading, and a first bonding pad 68 formed onthe lower layer 61 for providing a bonding area of the light-emittingstructure. In the present embodiment, the electrical connection E isarranged on the mesa area M. The first light-emitting structure unit 6comprises a first side surface 6 a, a second side surface 6 b and abottom surface 6 c connecting the first side surface 6 a and the secondside surface 6 b. The first side surface 6 a is inclined and comprises aslope which is gentler than a slope of the second side surface 6 b. Thefirst side surface 6 a is located near the first trench 65 and betweenthe first light-emitting structure unit 6 and the second light-emittingstructure unit 7. The second side surface 6 b is more distant from thefirst trench 65 than the first side surface 6 a is, and the second sidesurface 6 b is not between the first light-emitting structure unit 6 andthe second light-emitting structure unit 7. In one embodiment, the firstside surface 6 a can be a step-like side surface for improving the lightextraction efficiency. According to the present application, the firstlight-emitting structure unit 6 may comprise several edges from a topview of the light-emitting structure. In the present embodiment shown inFIG. 10, the light-emitting structure unit 6 comprises a rectangularbased shape comprising four edges. The first side surface 6 a and thesecond side surface 6 b can be respectively arranged on two of theedges. The first side surface 6 a can be connected to the second sidesurface 6 b directly, or the first side surface 6 a can be opposite tothe second side surface 6 b, such as shown in the present embodiment.The electrical connection E is arranged on the first side surface 6 a,while the second side surface 6 b is devoid of the electrical connectionE arranged thereon. An insulating layer 66 is arranged between the firstside surface 6 a and the electrical connection E to avoid undesirablecurrent conduction. Besides, the substrate 5 comprises a top surface 5 afaces the first light-emitting structure unit 6, and the first sidesurface 6 a and the second side surface 6 b directly connect to the topsurface 5 a of the substrate 5. The first light-emitting structure unit6 is formed on the top surface 5 a of the substrate 5, and the bottomsurfaces 6 c is adjacent to the top surface 5 a of the substrate 5. Froma top view of the light-emitting structure, the top surface 5 a isexposed by the first trench 65, while the side surface 5 b of thesubstrate 5 connects to the second side surface 6 b of the firstlight-emitting structure unit 6, so that the top surface 5 a of thesubstrate 5 is not exposed by the first light-emitting structure unit 6at the position where the second side surface 6 b located, which issimilar with the light-emitting structure units shown in FIGS. 1 and 8F.The first side surfaces 6 a connects to the bottom surface 6 c with afirst angle θ₁, and a second angle θ₂ is between the second side surface6 b and the bottom surface 6 c The second angle θ₂ can be larger thanthe first angle θ₁ In one embodiment, the first angle θ₁ can be smallerthan 90 degrees, preferably can be smaller than 80 degrees. In thepresent embodiment shown in FIG. 11, the first angle θ₁ can be betweenabout 40 degrees and 70 degrees. The second angle θ₂ can be betweenabout 80 degrees and 100 degrees, more preferably, the second sidesurface 6 b can be perpendicular with the bottom surface 6 c which meansthe second angle θ₂ can be approximately 90 degrees.

Likewise, the second light-emitting structure unit 7 can comprise thesame or similar structure with the first light-emitting structure unit6. The second light-emitting structure unit 7 includes lower layer 71,an upper layer 72, an active layer 73 between the lower layer 71 and theupper layer 72, a second current spreading layer 74, and a fingerelectrode 78, which are sequentially formed on a substrate 5. The secondlight-emitting structure unit 7 also comprises a first side surface 7 a,a second side surface 7 b and a bottom surface 7 c connecting to thefirst side surface 7 a and the second side surface 7 b, while the firstside surface 7 a is inclined and a slope of the first side surface 7 ais gentler than a slope of the second side surface 7 b. The first sidesurface 7 a is located near the first trench 65 and formed between thefirst light-emitting structure unit 6 and the second light-emittingstructure unit 7. The second side surface 7 b is more distant from thefirst trench 65 than the first side surface 7 a is, and the second sidesurface 7 b is not between the first light-emitting structure unit 6 andthe second light-emitting structure unit 7. According to the presentapplication, the second light-emitting structure unit 7 may compriseseveral edges from the top view of the light-emitting structure, and thefirst side surface 7 a and the second side surface 7 b can be arrangedon the different edges. The first side surface 7 a can be directlyconnected to the second side surface 7 b, or the first side surface 7 acan be opposite to the second side surface 7 b, such as shown in thepresent embodiment. Besides, in the embodiment, the side surface 5 b ofthe substrate 5 connects to the second side surface 7 b of the secondlight-emitting structure unit 7, so that the top surface 5 a of thesubstrate 5 is not exposed by the second light-emitting structure unit 7at the position where the second side surface 7 b located.

In the embodiment shown in FIG. 10, the light-emitting structurecomprises six light-emitting structure units electrically connected witheach other to form a high voltage LED, including the firstlight-emitting structure unit 6, the second light emitting structureunit 7 and the other four light-emitting structure units. An area of atop surface of the first light-emitting structure unit 6 is differentfrom that of the second light-emitting structure unit 7 from a top viewof the light-emitting structure. In the present embodiment, an area of atop surface of each of the other four light-emitting structure units islarger than that of the second light-emitting structure unit 7 andsmaller than that of the first light-emitting structure unit 6 from atop view of the light-emitting structure. The first light-emittingstructure unit 6 with the first bonding pad 68 has larger top surfacethan the other units for increasing the current spreading ability of thelight-emitting structure. A trench T between two of the light-emittingstructure units, which are other than the units 6 and 7, can be misalignwith the first trench 65 between the first light-emitting structure unit6 and the second light-emitting structure unit 7. In the presentembodiment, the light-emitting structure further comprises a secondtrench 65′ connecting to the first trench 65 and the second sidesurfaces 6 b. There is a turn 69 between the first trench 65 and thesecond trench 65′. The turn 69 in the embodiment can be blunt to avoidany electrostatic discharge issue incurred. However, in anotherembodiment, the turn 69 can be sharp. According to the embodiment asshown in FIG. 10, the first trench 65 comprises a first extendingdirection 65 d while the second trench 65′ comprises a second extendingdirection 65 d′ different from the first extending direction 65 d, and athird angle θ₃ is between the first extending direction 65 d and thesecond extending direction 65 d′. The value of the third angle θ₃ can berepresent to an angle of the turn 69. In the embodiment, the third angleθ₃ can be higher than 90 degrees, and the position of the turn 69 can beapproximately aligned with the edges of the upper layers 62, 72 of thefirst light-emitting structure unit 6 and the second light-emittingstructure unit 7 from the top view of the light-emitting structure. Forexample, the third angle θ₃ can be between about 120 degrees and 150degrees, more preferably, the third angle θ₃ can be between about 130degrees and 140 degrees.

It should be noted that the proposed various embodiments are forexplanation but not for the purpose to limit the scope of thedisclosure. Any possible modifications without departing from the spiritof the disclosure may be made and should be covered by the disclosure.The similar or same elements or the elements with the same referencenumeral in different embodiments have identical chemical or physicalcharacters. Besides, the elements shown in different embodimentsmentioned above could be combined or replaced with one another in propersituation. The connecting relationship of specific element particularlydescribed in one embodiment could also be applied in another embodiment,and the subject matter which comprises the elements in differentembodiments all fall within the scope of the following claims and theirequivalents.

What is claimed is:
 1. A light-emitting structure, comprising: a firstlight-emitting structure unit and a second light-emitting structureunit, adjacent to and spaced apart from each other; and an electricalconnection arranged on the first light-emitting structure unit and thesecond light-emitting structure unit, and electrically connecting thefirst light-emitting structure unit and the second light-emittingstructure unit; wherein the first light-emitting structure unitcomprises a first side surface and a second side surface; wherein thefirst side surface is between the first and the second light-emittingstructure units, and the second side surface is not between the firstlight-emitting structure unit and the second light-emitting structureunit; and wherein the first side surface is inclined and a slope of thefirst side surface is gentler than a slope of the second side surface.2. The light-emitting structure of claim 1, wherein the firstlight-emitting structure unit comprises a bottom surface connecting tothe first side surface and the second side surface, and a first anglebetween the first side surface and the bottom surface is smaller than 80degrees.
 3. The light-emitting structure of claim 2, wherein a secondangle between the second side surface and the bottom surface is largerthan the first angle.
 4. The light-emitting structure of claim 3,wherein the second angle is approximately 90 degrees.
 5. Thelight-emitting structure of claim 1, wherein from a top view of thefirst light-emitting structure unit comprises a rectangular shapecomprising four edges, and the first side surface and the second sidesurface are respectively arranged on two of the edges.
 6. Thelight-emitting structure of claim 1, further comprising a substratewhich the first and the second light-emitting structure units are formedthereon, wherein the substrate comprises a top surface facing the firstlight-emitting structure unit, and the first side surface and the secondside surface connect to the top surface.
 7. The light-emitting structureof claim 1, wherein the electrical connection is arranged on the firstside surface.
 8. The light-emitting structure of claim 1, wherein thesecond side surface is devoid of the electrical connection arrangedthereon.
 9. The light-emitting structure of claim 1, wherein firstlight-emitting structure unit comprises a lower layer and an upper layeron the lower layer; wherein the lower layer comprises a mesa areasurrounding the upper layer from a top view of the light-emittingstructure.
 10. The light-emitting structure of claim 9, wherein theelectrical connection is arranged on the mesa area.
 11. Thelight-emitting structure of claim 1, further comprising a substratewhich the first light-emitting structure unit and the secondlight-emitting structure unit are formed thereon; wherein a top surfaceof the substrate is not exposed by the first light-emitting structureunit at the position where the second side surface located.
 12. Thelight-emitting structure of claim 1, wherein the first light-emittingstructure unit and the second light-emitting structure unit are spacedapart by a first trench, and the first side surface locates nearer thefirst trench than the second side surface does.
 13. The light-emittingstructure of claim 12, further comprising a second trench connecting tothe first trench and the second side surface, and a turn between thefirst trench and the second trench.
 14. The light-emitting structure ofclaim 13, wherein from a top view of light-emitting structure, the firsttrench comprises a first extending direction and the second trenchcomprises a second extending direction different from the firstextending direction.
 15. The light-emitting structure of claim 14,wherein an angle between the first extending direction and the secondextending direction is between about 120 degrees and 150 degrees. 16.The light-emitting structure of claim 1, wherein an area of a topsurface of the first light-emitting structure unit is different fromthat of the second light-emitting structure unit from a top view of thelight-emitting structure.
 17. A light-emitting structure, comprising: afirst light-emitting structure unit and a second light-emittingstructure unit, adjacent to and spaced apart from each other, whereinthe first light-emitting structure unit comprises a step-like sidesurface facing the second light-emitting structure unit; an insulatinglayer, formed on the step-like side surface; and an electricalconnection, formed on the insulating layer and electrically connectingthe first light-emitting structure unit and the second light-emittingstructure unit.
 18. The light-emitting structure of claim 17, furthercomprising a substrate which the first and the second light-emittingstructure units are formed thereon; wherein first light-emittingstructure unit further comprises a second side surface different fromthe step-like side surface, and a top surface of the substrate is notexposed by the first light-emitting structure unit at the position wherethe second side surface located.
 19. The light-emitting structure ofclaim 17, wherein the first light-emitting structure unit furthercomprises a second side surface not between the first light-emittingstructure unit and the second light-emitting structure unit, and thestep-like side surface comprises a slope which is gentler than a slopeof the second side surface.
 20. The light-emitting structure of claim19, wherein the second side surface is devoid of the electricalconnection arranged thereon.